240 BACTERIA. 



as regards the tubercle bacillus may be acquired. It is 

 probable that the tuberculin acts as a stimulant on all cells, 

 and that to the increased metabolic changes that are set up 

 is due the general reaction that is described as following on 

 the exhibition of this material. 



That this is not entirely a fanciful explanation may be 

 argued from an example. It is a fact, well known to those 

 who have charge of tuberculous patients suffering from 

 diseased glands — scrofulous glands, as they are called — that 

 so long as these glands remain uninjured and are subjected 

 to no stimulation, and so long as the nutrition of the patients 

 keeps fairly good, they remain as a rule comparatively free 

 from pulmonary phthisis and other forms of tuberculosis ; 

 whilst other members of the same family, existing under the 

 same conditions, both as regards hygiene and nutrition, 

 become affected with the commoner and more fatal forms of 

 the disease. 



A further illustration may be taken from the difference 

 that exists between children of the lower classes and those 

 met with in other grades of society — children in a sick 

 children's hospital frequently having every organ crammed 

 with, or almost replaced by, tubercular nodules and cavities, so 

 that it seems marvellous that the unfortunate children could 

 have remained alive at all ; whilst children better nourished, 

 but not previously affected by any form of tubercle, appear 

 to succumb very easily, when comparatively localized tubercle 

 has been developed. In these cases, however, it is usually 

 found that some vital organ such as the brain is affected. 



It would appear that, in these cases, the tissues may de- 

 velop greater resistance in consequence of the circulation 

 in the fluids of the body of the soluble products ; but 

 that when this acquired resistance is once lost, or is over- 

 come, the stimulation exhausts the cells, and they now 

 more easily fall a prey to the active tubercle bacilli. It 

 must, however, in this connection, be pointed out that the 

 products of the tubercle bacillus, or sterilized cultures of the 

 organism, when introduced subcutaneously into healthy 

 fowls or guinea-pigs, produce a condition which is spoken of 

 as "marasmus ;" and as early as i879,Maffucci, as the result 

 of a series of experiments, concluded that these sterilized cul- 

 tures when left in the body, exerted such a marked influence on ■ 

 the tissues, that they induced emaciation, atrophy of the liver 



